iStock/Thinkstock(NEW YORK) -- Legal scholars are pushing back against a claim by one of President Donald Trump's personal lawyers that his client "cannot obstruct justice" because of his role as the country’s “chief law enforcement officer.”

Trump "has every right to express his view of any case,” his attorney John Dowd said Monday, citing Article II of the Constitution, which establishes the executive branch of the U.S. government.

But history and the law aren’t on Dowd’s side, some legal experts said.

Presidents Richard Nixon and Bill Clinton faced articles of impeachment that included obstruction of justice.

"No one in the Judiciary Committees during the Clinton and Nixon cases ever claimed that the president is incapable of obstructing justice," constitutional scholar Michael Gerhardt of the University of North Carolina School of Law said.

The issue resurfaced this week after a Trump tweet, which Dowd has since said he wrote, stated that Trump knew his former national security adviser, Michael Flynn, lied to the FBI when he was asked to resign in February, three months before Trump fired FBI director James Comey in May.

If that’s the case, some believe, then there’s a plausible argument to be made that Trump obstructed justice by firing Comey in order to affect the FBI’s investigation of Russian attempts to influence the 2016 U.S. election and any possible collusion by Trump associates.

A president “can discharge an investigation but he can’t dismiss it for whatever reasons he wants,” Gerhardt told ABC News. “There are illegitimate grounds for exercising a lawful power.”

Gerhardt mentioned, for example, that an employer can legally fire an employee, but not on account of his or her race, religion or sex. In law, intent can matter.

Gerhardt said that no one, including the president, is above the law and called the claim that Trump can’t obstruct justice is “absurd.”

But constitutional legal scholar Alan Dershowitz offered some support of Dowd’s interpretation of the law. Firing Comey in itself cannot be obstruction of justice because the president had the power to do so, unless there are "clearly illegal acts" and a criminal intent, Dershowitz told Fox News Monday.

“I think if Congress ever were to charge him with obstruction of justice for exercising his constitutional authority under Article II, we'd have a constitutional crisis,” Dershowitz said. “You cannot charge a president with obstruction of justice for exercising his constitutional power.”

John Lauro, a defense lawyer with the Lauro Law Firm and a former prosecutor, said Dershowitz is correct in reference to Comey’s firing, but that doesn't mean a president can never face obstruction of justice charges.

“Professor Dershowitz is absolutely correct: In order to make a criminal case, a prosecutor has to prove beyond a reasonable doubt that the president fired Comey with the specific intent to impede a criminal investigation,” Lauro said. “Based on what we know now, any prosecutor who brought such a charge would be laughed out of court.”

Professor Adam Samaha of NYU School of Law made this distinction: “If the president is acting within the scope of his exclusive constitutional authority, of course, that cannot and should not be made a crime. But the debate should be, ‘What falls within his exclusive constitutional authority,’” which Samaha called a complex question.

On Tuesday, Even Ty Cobb, the White House lawyer handling Russia matters, contradicted the assertion by Trump’s personal attorney Dowd, first reported by Axios, that the president cannot possibly be guilty of obstruction of justice.

To his knowledge, Cobb said in a statement to ABC News, “There is no strategy of which I'm aware to rely boldly on the proclamation that obstruction is always impossible with regard to a president. I expect a fact-based exoneration that does not require that level of legal analysis.”